/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
 * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
 * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package com.vip.vjtools.vjkit.io.type;

import java.io.Serializable;
import java.io.Writer;

/**
 * JDK的java.io.StringWriter使用StringBuffer，移植Commons IO使用StringBuilder的版本.
 * 
 * https://github.com/apache/commons-io/blob/master/src/main/java/org/apache/commons/io/output/StringBuilderWriter.java
 * 
 * {@link Writer} implementation that outputs to a {@link StringBuilder}.
 * <p>
 * <strong>NOTE:</strong> This implementation, as an alternative to <code>java.io.StringWriter</code>, provides an
 * <i>un-synchronized</i> (i.e. for use in a single thread) implementation for better performance. For safe usage with
 * multiple {@link Thread}s then <code>java.io.StringWriter</code> should be used.
 *
 * @since 2.0
 */
public class StringBuilderWriter extends Writer implements Serializable {

	private static final long serialVersionUID = -146927496096066153L;
	private final StringBuilder builder;

	/**
	 * Constructs a new {@link StringBuilder} instance with default capacity.
	 */
	public StringBuilderWriter() {
		this.builder = new StringBuilder();
	}

	/**
	 * Constructs a new {@link StringBuilder} instance with the specified capacity.
	 *
	 * @param capacity The initial capacity of the underlying {@link StringBuilder}
	 */
	public StringBuilderWriter(final int capacity) {
		this.builder = new StringBuilder(capacity);
	}

	/**
	 * Constructs a new instance with the specified {@link StringBuilder}.
	 *
	 * <p>
	 * If {@code builder} is null a new instance with default capacity will be created.
	 * </p>
	 *
	 * @param builder The String builder. May be null.
	 */
	public StringBuilderWriter(final StringBuilder builder) {
		this.builder = builder != null ? builder : new StringBuilder();
	}

	/**
	 * Appends a single character to this Writer.
	 *
	 * @param value The character to append
	 * @return This writer instance
	 */
	@Override
	public Writer append(final char value) {
		builder.append(value);
		return this;
	}

	/**
	 * Appends a character sequence to this Writer.
	 *
	 * @param value The character to append
	 * @return This writer instance
	 */
	@Override
	public Writer append(final CharSequence value) {
		builder.append(value);
		return this;
	}

	/**
	 * Appends a portion of a character sequence to the {@link StringBuilder}.
	 *
	 * @param value The character to append
	 * @param start The index of the first character
	 * @param end The index of the last character + 1
	 * @return This writer instance
	 */
	@Override
	public Writer append(final CharSequence value, final int start, final int end) {
		builder.append(value, start, end);
		return this;
	}

	/**
	 * Closing this writer has no effect.
	 */
	@Override
	public void close() {
		// no-op
	}

	/**
	 * Flushing this writer has no effect.
	 */
	@Override
	public void flush() {
		// no-op
	}

	/**
	 * Writes a String to the {@link StringBuilder}.
	 *
	 * @param value The value to write
	 */
	@Override
	public void write(final String value) {
		if (value != null) {
			builder.append(value);
		}
	}

	/**
	 * Writes a portion of a character array to the {@link StringBuilder}.
	 *
	 * @param value The value to write
	 * @param offset The index of the first character
	 * @param length The number of characters to write
	 */
	@Override
	public void write(final char[] value, final int offset, final int length) {
		if (value != null) {
			builder.append(value, offset, length);
		}
	}

	/**
	 * Returns the underlying builder.
	 *
	 * @return The underlying builder
	 */
	public StringBuilder getBuilder() {
		return builder;
	}

	/**
	 * Returns {@link StringBuilder#toString()}.
	 *
	 * @return The contents of the String builder.
	 */
	@Override
	public String toString() {
		return builder.toString();
	}
}
